The present invention relates to an apparatus for the delivery of a beneficial agent to an animal.
The automated dispensing of liquid medicine, such as analgesia, by infusion to relieve postoperative pain is increasingly being effected by using patient controlled or programmable infusion pump units. Typically, a programmable infusion pump unit includes an electronic infusion unit which can be readily activated by a patient. The patient is free to increase the dosage of medication in response to the pain experienced by repeatedly depressing an actuator. As the medication administered by such infusion pump units is often a narcotic analgesic, the unit is also equipped to limit the maximum dosage thus avoiding possible negative effects given the onset of an overdose.
The use of patient controlled and programmable infusion pumps has gained widespread acceptance based on a combination of their reliability in the timely administration of medication and the effect of relieving health care workers of the routine task of administering dosages of medication.
Animals undergoing surgery in a research or veterinary environment also invariably experience pain. In such an environment, ethics personnel closely supervise post-operative pain management in order to minimise any pain and suffering an animal may have. The current standard of care requires the animal to be assessed post-operatively by an animal-care giver, and to be medicated appropriately when there is a subjective impression of the presence of pain.
As animals cannot communicate verbally or cognitively activate an actuator in response to increased pain, one of the chief modalities used to make the assessment of pain is motion and agitation. The more extreme and rapid the motion, the more intense the pain which is being experienced by the animal. While this provides indicia to an animal care-giver of when to deliver appropriate analgesic medication, it often means that the animal is medicated only after the pain has reached intolerable levels. In addition, there is invariably a delay between animal experiencing the pain, the physical manifestation of the animal""s distress, and the interpretation of the manifestation by the animal care-giver, who may have a number of animals in her care or may not have the animal under her surveillance at all times.
It is therefore desirable to provide an apparatus which can automatically measure the level of pain being experienced by an animal by interpreting the characteristics of the animal""s motion. In addition, the level of pain can be used to provide for the infusion of an analgesic agent as an appropriate response with a dispensing apparatus operatively connected to the apparatus for measuring the level of pain; such an apparatus would aid the animal care-giver in the timely delivery of an analgesic agent thus reducing the animal""s distress and freeing the animal care-giver to undertake other tasks.
It is an object of the present invention to provide an apparatus for the indication of pain felt by an animal. In accordance with the invention, this object is achieved with an apparatus comprising:
(a) at least one motion sensor for sensing motion of the animal, each of said motion sensors having an output; and
(b) a control unit operatively connected to the output of each motion sensor, the control unit being capable of generating a trigger signal when the output of the motion sensor exceeds a predetermined level, said trigger signal being indicative of the level of pain experienced by the animal.
The trigger signal can be used to trigger a visual or audible alarm, thereby calling an animal care-giver""s attention to the animal in order to provide an adequate response.
Alternatively, the apparatus according to the invention can also further include a dispensing means operatively connected to the trigger signal of the control unit, the dispensing means causing a beneficial agent to be discharged from a storage chamber into the animal upon reception of the trigger signal. Consequently, the administration of medication can be automated in response to the output of the motion sensor, representative of the movement and agitation of the animal. In a preferred embodiment, the dispensing means is similar to a PCA as used for humans.
The present invention and its advantages will be more easily understood after reading the following non-restrictive description of preferred embodiments thereof, made with reference to the following drawings in which:
FIG. 1 is a block diagram of an apparatus to deliver a beneficial agent to an animal according to a preferred embodiment of the invention;
FIG. 2 is a detailed perspective view of a platform leg with strain gauge transducer attached; and
FIG. 3 is a schematic representation of an accelerometer for use in the apparatus according to the invention.